Rectifier



Dec. 16, 1930. F. GRAY 1,784,869

RECTIFIER Filed March 51, 1926 Frank Gray of potential impressed on the respective elec-l Patented Dec. 16, 1930 UNITED. STATES v PATENT OFFIC FRANK GRAY, OF NEW YORK, N. Y., ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK RECTIFIER Application filed March 81, 1926. Serial No. 98,658.

This invention relates to rectifying devices and more particularly to gaseous discharge rectifiers.

Such devices are capable of a. wide range of uses, especially in the telephone art, and par ticularly in selective systems, such as party line ringing systems. However, the cost and maintenance of such devices have been prohibitive for such adaptation and the directional characteristics have not been certain. Furthermore, their operating life has been 1short and the voltage break-down relatively iigh. I

The principal object of this invention is to provide a gaseous rectifier having uni-directional discharge characteristics.

A further-object is to provide such a device which is inexpensive, of simple and rugged construction, and capable of functioning over an extended period without attention.

In accordance with this invention these objects are accomplished by providing two main cold electrodes, and an auxiliary or screen electrode interposed between the main electrodes and relatively close to one of these electrodes. These electrodes are enclosed in a vessel containing an inert gas, such as argon, and the screen electrode is electrically connected to one of the main electrodes through a high resistance. Either one of the main electrodes can function as the cathode or anode of the device, since the discharge flow is dependenton the polarity of a source trodes. For instance, if the electrode surrounded by theauxiliary electrode is positively charged and the other electrode is charged with a negative potential, these main electrodes function as anode and cathode respectively. Therefore, the discharge passes from the anode to the cathode and a large current flows. However, when the electrode surrounded by the auxiliary electrode is charged with a negative potential and the other electrode charged positively, it is very difiicult for the discharge to pass through the auxiliary electrode. If the voltage is not too excessive, the entire discharge passes between the positively charged anode and the auxiliary electrode, and the high resistance permits only a small current to flow. This arrangement provides a dis charge device in which a flow of current is uni-directional, i. e. a large current flow can only occur between the main electrodes when the electrode connected to and surrounded by the screen electrode is charged positive,

and substantially no current can flow in the opposite direction.

The invention is illustrated in the recompanying drawing in which Fig. 1, shows in perspective a discharge tube with parts broken away to show the internal elements. Fig.2 is a cross-sectional view of the discharge tube showing the electrode connections, and Fig. 3 is a partial schematic of a selective signaling party line embodying this invention.

Referring to Fig.1, the discharge device comprises a glass enclosing vessel 10 in which are placed two similar disc electrodes 11 and 12. These electrodes, which constitute the main electrodes of the device, operate in the cold state in contra-distinction to an electron discharge and are preferably of aluminum. An auxiliary or screen electrode 13, also of aluminum is preferably formed into a cup-shape and substantially surrounds the main electrode 12. The auxiliary or screen electrode 13 is preferably placed closer to the electrode 12 for reasons to be hereinafter explained. The'electrode 11 is supported in the vessel 10 by means of a leading in wire 14 which is sealed through one end of the glass vessel. The disc electrode 12 is supported in the vessel by means of the leading-in wire 15 which is sealed in the opposite end ofthe glass vessel 10 and supports the electrode 12 in proper space relation with respect to the electrode 11, The cup-shaped screen electrode 13 is supported in the. glass vessel by a'leading-in wire 16 which is connected externally to the leading-in wire 15 by a high resistance 17 as shown in Fi 2. The enclosing vessel 10 is evacuated b all gases and vapors and provided with a filling of inert gas, such, for example, as argon, at a pressure of about five to twenty millimeters of mercury. This gaseous atmosphere :facilitates the passage of the discharge in the device.

The arrangement of the auxiliary electrode 13, with respect to the electrodes 12 and 11, has a large'directional effect on the passage of current through the device. Either of the main electrodes may function as the cathode or anode dependent on the voltagepolarity impressed on the respective electrodes. For instance, if the electrode 11 is he atively charged it becomes; the cathode, the ischarge passes from the electrode 12, acting as the anode, to electrode 11 and a large current flows. However, when the electrode 11 is positively charged it becomes the anode and it is difficult for the discharge to pass through the auxiliary electrode 13. If the voltage is not too excessive the discharge passes only between the anode 11 and the auxiliary electrode, then through the high resistance 17, in which case substantially no current flows. The explanation of this effect is as follows: in a gaseous discharge there is a rapid drop in potential near the cathode which is necessary for the passage of the discharge. When the electrode 12 is a cathode the auxiliar electrode is in the region of this cathode rop and is at a potential of the same sign as thecathode. The auxiliary electrode therefore tends to decrease the rapidity of the potential drop and conse uently interferes with the passage of the disc ar e from the electrode 11 to electrode 12. Un er this condition the discharge takes place between the anode 11' and the auxiliary electrode 13- and thecurrent is limited by the high resistance 17. When electrode 12 is an anode, namely, charged with a positive potential, the auxiliar electrode 13 does not interfere with the disc arge from the anode to the cathode and a large current flows. Thus it will be seen thata lar e directional effect is obtained in the disc arge device, depending on the flow of-current between the main electrodes 111 and 12.

In selective signaling systems, such as a four party telephone line disclosed in Patent No. 1,517,857, issued December 2, 1924, to P. Norton and D. T. May, pulsating or intermittent current is transmitted over either side of the telephone'line 'to selectively operate asignaling device or ringer to the exclusion of the other ringers on the line. Such a system is schematically shown in Fig. 3, and

illustrates a four party line inwhich a discharge rectifier, made inaccordance with this invention is included in. series with the ringer 19 ofeach station. In such a system positive or negative current is transmitted over either side of the line to operate a single signaling device. For example; if position 1 is 5 to be operated the discharge rectifyingldevice '20 is connected in the circuit with trode 12, functioning as an anode, connected 'to the line, and the electrode 11 functioning e elecas the cathode, connected to the ringer 19 and to ground. Positive pulsating current is transmittedover the lower side of the line and since the rectifier 20, in position 1, has the anode 12 connected to the lower side of the line a large current will flow between the main electrodes to actuate the ringer 19. The positive pulsating current does not operate position 2, since the discharge device 20 is reversed in this position having its electrode 11 connected to the line and electrode 12 connected to the ringer 19 through ground. No current passes be-.

tively over the upper side of the line to operate the ringer 19 at these positions, the operation being performed in the same manner as explained in connection with positions 1 and 2. The adaptation of a discharge device made in accordance with this invention, to a selective ringing system, such as a arty telephone line, increases the selectivlty of the line 'and also eliminates the maintenance of apparatus heretofore used, such as relays and condensers.

While the invention has been disclosed with respect to a particular use, it is to be understood that the invention is applicable to a wide range of uses, for instance, the invention may be utilized to prevent sparkin at relay contacts, or it may be used as a directional rectifier 1n battery charging also in connection with wireless equipment, and in other electrical systems in Whlch it is necessary to secure a directional discharge.

What is claimed is:

1. A discharge device comprisin a containing vessel, a filling of inert ast erein, a pair of opposed disc shaped co d main electrodes comprising an anode and a cathode, a perforated cup-shaped cold electrode interposed between said mainelectrodes and having a surface parallel with and surrounding the periphery of one of said electrodes, and a high resistance connection between said perforated electrode and one of said main electrodes.

2. A discharge device comprisin a containing vessel, a filling of inert gas t erein, a

pair of aluminum disc electrodes, an aluminum cup-shaped screen electrode substantially enclosing one of sand electrodes, and an external resistance connection between sald screen electrode and said enclosed disc electrode.

' 3. A discharge devlce comprising a conconnecting said screen metalhc d1sc electrodes,

screen electrode between said. cathode and v anode, the walls of said screen electrode being relatively close to and substantially'enclosing said cathode, and a high resistance electrode to said cathe. 4. A discharge containing a filling of inert gas, a pair of a cup-shaped auxiliary electrode positioned between said electrodes and substantially enclosing-one of said electrodes, and a high resistance connected between said auxiliary electrode and one of said metallic electrodes.

In .witness whereof, I hereunto subscribe my name this 23d day of March, A. D1926. FRANK GRAY.

device comprising a vessel 

